“Why didn’t you tell me about this when it happened?”
There were several possible acceptable answers to this for Toby: that she didn’t take it seriously, that she didn’t want to hurt Toby, that she barely registered it the minute it happened, so in love was she with her husband—all these would have been fine. Instead she went with: “I didn’t think to. It was just something that happened at work. Do you tell me everything that happens at your work? Actually, don’t answer that, maybe you do.”
He didn’t like how not a part of this story he was. He didn’t like that he was only hearing about this because it was mitigating information against something else that had happened that day. He didn’t like that she didn’t seem to think her marriage was relevant to all of this.
i like the bit at the end of her dialogue about him telling her everything about his job [which she complains about in a beautiful scathing way later on]